The radiation dose absorbed by the patient during a CT scan can be estimated using a knowledge of patient body habitus and information made available by the manufacturer and confirmed by a qualified medical physicist. One must always be mindful of the balance between this dose and the radiation delivered to the CT detector assembly since it is this radiation that generates the signals required for producing the CT images. CT machine parameters under the direct control of the operator provide the opportunity for optimizing image quality while limiting patient dose. We will discuss the effect that these adjustable CT parameters have on both dose and image quality and the concept, measurement, interpretation, and uses of CTDIvol. We will also discuss the effect that patient size has on radiation dose and describe SSDE, the size-specific dose estimate that helps to account for patient size when estimating the dose delivered to the patient by the CT machine.

Meet the speaker, Donovan M. Bakalyar, Ph.D., FACR, Imaging Physicist in the Henry Ford Health System. Dr. Bakalyar focuses much of his attention on CT. He has served on several AAPM task forces and committees and is currently the chair of AAPM Task Group 200.